1. Field of the Invention
The present invention relates to methods and apparatus for analyzing the subterranean. In another aspect, the present invention relates to methods of and apparatus for analyzing formation fluids and gases. In even another aspect, the present invention relates to distinguishing formation fluids and gases from drilling contaminates in methods of and apparatus for analyzing formation fluids and gases. In still another aspect, the present invention relates to utilizing mass spectroscopy in methods of and apparatus for analyzing formation fluids and gases. In yet another aspect, the present invention relates to methods and apparatus for analyzing formation fluids and gases, utilizing tags or markers in the well fluid. In even still another aspect, the present invention relates to methods and apparatus for analyzing formation fluids and gases, utilizing isotope tags or markers in the well fluid.
2. Description of the Related Art
Hydrocarbon exploration and data gathering of wells can be accomplished by utilizing wireline logs or logging while drilling tools (LWD) to obtain certain physical characteristics of a formation. Wireline logs require an umbilical (e.g. wireline, tool push-in, coiled tubing) from the surface to provide electrical power and are generally utilized after a well is drilled. LWDs are used to provide quantitative analysis of sub-surface formations during the actual drilling operation. LWDs typically include their own power source as the LWD string is an integral part of the bottom hole assembly and it would be impractical to connect an umbilical from the surface to provide electrical power or other requirements of the various LWD tools. The formation characteristics monitored by wireline logs and LWDs can include formation density, porosity, and water saturation. However, more detailed analysis would aid in characterization of a formation.
The analysis of the physical properties of the formation fluids, for example to determine relative amounts of oil, gas, and water, and the density, viscosity and compressibility of the fluid, is also of importance in determining the physical properties of a particular well.
However, the means of analysis of such formation fluids must be able to discriminate between the formation fluids and any drilling fluid components mixed with or intermingled with the formation fluids. For example, the hydrocarbon and/or water phases of the formation fluid may be contaminated with hydrocarbon and/or water components from the drilling fluid and/or mud filtrate.
For example, typically, the drilling fluids or muds will be either water or oil based. While oil base fluids are particularly useful in unconsolidated and water-susceptible formations, the hydrocarbons present in the drilling fluid may mask the formation fluids in the drilling mud returns, thus preventing the identification of formation hydrocarbons. Likewise, even when water based muds are used, diesel or other hydrocarbons may be added to aid in lubricating the drill bit, and likewise cause a similar masking of formation hydrocarbons. Furthermore, the water of the water based mud may mask the formation water phase, and cause a distortion of the formation hydrocarbon/water ratio.
The quantitative analysis of the constituents of the formation fluid distinguished from drilling fluids could be accomplished by the use of mass spectrometry which is a known analytical technique utilizing an instrument called a mass spectrometer.
A mass spectrometer generally consist of four components, an inlet system, an ion source, an analyzer, and a particle detector. Typical, unlimited examples of inlet systems include probe, chromatography or capillary electrophoresis. The ion source operates under high vacuum and employs some means of ionizing molecular samples. Typical ion sources bombard sample molecules with a high energy electron beam thereby shattering the sample into molecular and fragment ions. The analyzer separates the ions according to their mass to charge ratios. Typical analyzers include magnetic, quadrupole, ion trap, fourier transform and time of flight. The particle detector registers the intensity of the signal generated by the molecular and fragment ions. Non-limiting examples of suitable analyzers include channeltrons, electron multipliers, and microchannel plates.
Generally, in operation, a sample is introduced into a mass spectrometer and subject to ionization. The positive ions (molecular and fragment ions)are accelerated in a vacuum through a magnetic field or an electric field and sorted on the basis of mass to charge ratio (m/e). The highest molecular weight peak observed in a spectrum will typically represent the parent molecule minus an electron.
Present methods and apparatus require that a sample be removed from the well and analyzed by mass spectroscopy either at the well site or remote to it.
In some instances, no steps are taken to maintain the sample at the high pressures of the subterranean form which it was sampled, which may cause a phase change in part or all of the sample, and possibly skewing the results of any analysis. For while the sample may later be xe2x80x9crepressurized,xe2x80x9d there may be hysteresis effects that come into play resulting in different composition results, or some or all of the sample may be xe2x80x9clostxe2x80x9d through xe2x80x9cventingxe2x80x9d bringing it to the surface, and may skew the results.
In other instances, while steps are taken to maintain the sample at the high pressures of the subterranean from which it was sampled, at some point (i.e., as a non-limiting example, during transfer from the sample container to an analyzer) the sample pressure may be reduced, which again, may possibly skew the results of any analysis.
Furthermore, even with advanced spectrometry techniques, it is still sometimes difficult to distinguish in the sample, contributions by formation fluids from contributions by drilling fluids.
Therefore, there is still a need for a method and apparatus to perform more detailed down-hole analysis of formation fluids.
There is another need in the art for a method and apparatus to perform more detailed down-hole analysis of formation fluids which can distinguish between formation fluids and drilling contaminants.
There is even another need in the art for a method and apparatus to perform more detailed down-hole realtime analysis of formation fluids which can distinguish between formation fluids and drilling contaminants.
These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
It is an object of the present invention to provide for a method and apparatus to perform more detailed down-hole analysis of formation fluids.
It is another object of the present invention to provide for a method and apparatus to perform more detailed down-hole analysis of formation fluids which can distinguish between formation fluids and drilling contaminants.
It is even another object of the present invention to provide for a method and apparatus to perform more detailed down-hole realtime analysis of formation fluids which can distinguish between formation fluids and drilling contaminants.
These and other objects of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
According to one embodiment of the present invention there is provided an analysis module designed to be positioned in a well bore which includes a sampler system and a mass spectrometer.
According to another embodiment of the present invention there is provided a method for analyzing formation fluids which includes the steps of: positioning a mass spectrometer in a well bore; obtaining a sample of formation fluid; introducing the sample into the mass spectrometer; and processing the data received from the mass spectrometer to determine the molecular constituents of the formation fluid.
According to even another embodiment of the present invention, there is provided a method for analyzing well bore fluids. The well bore fluids generally include well fluids added to the well bore and formation fluids from the subterranean formation. The method generally includes adding an isotrope marker or tag to a fluid to form a well fluid. The method next includes contacting in the well bore, the well fluid with the formation fluid. The method also includes analyzing the well bore fluid to determine the components of the formation fluid.
According to still another embodiment of the present invention, there is provided a method for analyzing well bore fluids in a well bore. The method generally include positioning a mass spectrometer in the well bore. The s method also includes sampling the well bore fluids, and then analyzing the well bore fluids with the mass spectrometer.
According to yet another embodiment of the present invention, there is provided an apparatus positioned in a well bore penetrating the subterranean. The apparatus includes a drilling string or umbilical, positioned in the well bore, and extending from the surface into the subterranean. The apparatus also includes a sonde positioned in the well bore, and supported by the drilling string or umbilical, wherein the sonde comprises a mass spectrometer.